Comparative Performance of Winter Wheat Genotypes Under Dryland and Irrigated Environments.

Development of improved winter wheat cultivars is an important objective of the Turkey/CIMMYT/ICARDA International Winter Wheat Improvement Program (IWWIP), a cooperative project involving Ministry of Agriculture and Rural Affairs of Turkey, CIMMYT and ICARDA. Each year, IWWIP evaluates wheat genotypes across diverse semi-arid and irrigated environments within Central and West Asia and North Africa and upon request beyond. Selected collaborators evaluated the advanced lines targeted for irrigated conditions (in a set of yield trials called “IWWYT-IR”) and for semi-arid environments (IWWYT-SA) under irrigated management. The first study, examined comparative performance of the wheat genotypes targeted individually for irrigated and semi-arid environments, but tested under irrigated management. The second analysis examined IWWYT-SA trials managed under high and low production systems. The IWWYT-IR trials were rarely tested under dryland, making it impossible to test also the reverse hypothesis. The results show the yield of the highest yielding genotypes in IWWYT-IR and IWWYT-SA were comparable under irrigated management, suggesting that certain genotypes developed for dryland also possess yield potential that could efficiently utilize management practices for high productivity. In the second analysis of IWWYT-SA in four years, different genotypes showed superior performance under low and high productive environments, demonstrating their specific adaptability. However, six out of 20 highest yielding genotypes in IWWYT-SA showed superior performance both under low and high productive environments. This shows that while in general different sets of genetic materials are needed under strictly semi-arid and irrigated environments, a few lines targeted towards stressed conditions in fact possess yield plasticity resulting in superior performance both under dryland and irrigated conditions. Such genotypes express what is called input responsiveness and would be expected to have performance stability across diverse environments (spatial stability) and over years varying in weather patterns (temporal stability). These findings provide valuable information for winter wheat improvement programs.